Currently, the heat assisted magnetic recording (HAMR) method with writing and magnetic flux reading is well proposed for increasing the perpendicular recording density of the magnetic disk, where the amorphous rare earth-transition metal (RE-TM) thin films are usually applied as the recording medium therefor.
The RE-TM thin film is advantageous in having the perpendicular magnetic anisotropy above 106 erg/cm3 and exhibiting the perpendicular magnetization, and thus it is always considered as a candidate for HAMR. Generally, the recording medium for HAMR needs to be provided with the following properties including a satisfactory magneto-optical writing performance, a large saturation magnetization, Ms, that generates a sufficient magnetic flux for the giant magnetoresistance (GMR) head or the tunneling magnetoresistance (TMR) head readout, and a large perpendicular coercivity, Hc⊥, so as to resist the self-demagnetization. Apparently, the traditional magneto-optical (MO) recording medium is not suitable for being applied for HAMR because such medium fails to generate sufficient magnetic flux for GMR or TMR head readout owing to the relatively lower saturation magnetization (Ms) value thereof.
For overcoming the drawbacks of the conventional recording medium with a relatively lower Ms value, the prevent invention provides an improved HAMR medium of a FePt/CoTb bi-layer structure, in which the Ms value and Hc⊥ value thereof are significantly enhanced owing to a relatively high Ms value of the FePt (001) thin film and a relatively high exchange energy at the interface between the FePt/CoTb bi-layer structure.